Orthodontic brackets represent a principal component of corrective orthodontic treatments devoted to improving a patient's occlusion. In conventional orthodontic treatments, an orthodontist or an assistant affixes brackets to the patient's teeth and engages an archwire into a slot of each bracket. The archwire applies corrective forces that coerce the teeth to move into correct positions. Traditional ligatures, such as small elastomeric O-rings or fine metal wires, are employed to retain the archwire within each bracket slot. Due to difficulties encountered in applying an individual ligature to each bracket, self-ligating orthodontic brackets have been developed that eliminate the need for ligatures by relying on a movable portion or closure member, such as a latch, clip or slide, for retaining the archwire within the bracket slot.
One such closure member for retaining the archwire within the bracket slot is a rotatable clip. The rotatable clip is movably mounted to the bracket body so as to be rotatable about a central clip axis. Rotation of the clip about the central axis moves the closure member between an opened position and one or more closed positions. By way of example, the rotatable clip may have an opened position in which the clip does not block or otherwise impede the insertion of the archwire into the archwire slot of the bracket. From this position, the clip may be rotated about the central axis to a closed position wherein a portion of the clip closes off the archwire slot, thereby retaining the archwire therein. Such an orthodontic bracket is disclosed in U.S. Pat. No. 8,162,660, the disclosure of which is incorporated by reference herein in its entirety.
One challenge with self-ligating orthodontic brackets, and certainly with rotating clip orthodontic brackets, is designing an effective retention mechanism for movably coupling the clip to the bracket body. For example, in one approach, the rotating clip has a radially-extending rib that is received within an annular groove in the bracket body. Once the rib is positioned in the annular groove, such as during the assembly process, the clip may not be separated from the bracket body (such as by pulling it away from the bracket body in, for example, a buccal or labial direction), but is rotatable relative to the bracket body between its opened position and a closed position.
In addition, orthodontists and other orthodontic professionals may find it desirable to have a positive indication of when the rotating clip is in the opened position and/or a closed position. This not only notifies the orthodontist when the clip is in the opened or closed position, but also aids in preventing or reducing the possibility of accidental or unintentional movement. While the rib/groove arrangement of prior rotating clip orthodontic brackets allows the clip to rotate between its various positions, there is nothing inherent in that arrangement that provides a positive indication of clip position. If such a feature is desired, it is typically incorporated separately. By way of example, in one approach, the rotating clip includes a bump or projection which is received in a dimple or recess of the bracket body when the rotating clip is in a closed position.
While self-ligating brackets have been generally successful, manufacturers of such brackets continually strive to improve the use and functionality of these orthodontic brackets. In this regard, there exists a need for a self-ligating orthodontic bracket having a rotating clip type of closure member that has an improved retention mechanism that not only retains the clip to the bracket body, but also provides a positive indication of clip position.